Can we get ninja to figure out when it should run `regenerate` and to do it automatically?

[rrbutani]

Can we get ninja to figure out when it should run `regenerate` and to do it automatically?

[rrbutani]

Indeed we can!

We can get the build.ninja build statement to depend on all the folders that we look for source code in and we know to exist when gen is run. When source files are added or removed it'll trigger a regenerate.

We'll always use the project folder (.) as a dependency since it'll always exist; this has the nice side-effect of resulting in a regenerate when source folders (like src and asm) are added in the project folder.

I don't think this will result in lots of unnecessary regenerates, but it will have the undesirable side-effect of breaking the build file when source directories (even empty ones!) that were previously there are deleted. You'll have to manually rebuild if you do this.